“It felt like cramp; it wasn’t so bad but I didn’t want to take any risks,” the Polish marksman had told German publication Sport Bild following his team’s 2-0 triumph against their Saxony-based Bundesliga title rivals.

Watch:Javi Martinez points to Bayern's "tough schedule."

Shortly after registering his side’s second goal of the day – and his tenth in the Bundesliga this season – Lewandowski gestured to the bench while pointing to his right hamstring and was subsequently replaced by Arturo Vidal.

"I don’t think [the injury] is bad,” Bayern coach Jupp Heynckes had assured reporters afterward. “It has to do with the heavy load placed on the player these past weeks; he has little support in his playing position and that’s something we need to look to sort out,” the tactician added.

The 29-year-old forward agreed, explaining, “This season has been very demanding on me. I’m playing at Bayern and with Poland every three days since the start of the season. No player can play 90 minutes in every single game. However, at this moment there is no other option as we don’t have backup in my position.”

Following the midweek trip to Celtic, the Bundesliga leaders face rivals and Lewandowski's former club Borussia Dortmund at SIGNAL IDUNA PARK on Saturday, which Bayern Chairman Karl-Heinz Rummenigge says the striker will be fit for.

“In my opinion, the Celtic game is as important as the Dortmund match,” Lewandowski said. “We must win [in Glasgow].” Currently second in their Champions League section, Bayern hold a three-point lead over Celtic, but also trail leaders Paris Saint-Germain by three points.